style.css

body{
    text-align: center;
}

.box-container{
    display: flex;
    flex-direction: column;
    width:fit-content;
    height: fit-content;
    position: absolute;
    left:41%;
}

.box-container1{
    display: flex;
}

.box-container2{
    display: flex;
}

.btn{
    height:6rem;
    width:6rem;
    border:5px solid black;
    border-radius: 2rem;
    margin:1rem;
   display: flex;
   flex-direction: column;
   justify-content: center;
}

.red{
    background-color:#d95980 ;
}

.yellow{
    background-color:#f99b45 ;
}

.green{
    background-color:#63aac0 ;
}

.purple{
    background-color:#819ff9 ;
}

.gameflash{
    background-color: white;
}

.userflash{
    background-color: aqua;
}

.endflash{
    background-color: red;
}

.dispnone{
display: none;
}

#guide{
    text-align: center;
    position: relative;
    top:20rem;
}

#Click{
    width: fit-content;
    height: 3rem;
    background-color: rgb(3, 247, 218);
    color: black;
    text-align: center;
    border-radius: 2rem;
    border:2px solid black;
    transition: all 0.5s ease-in-out 0s;
    font-weight: bolder;
    font-size: large;
}

#Click:hover{
    transform: scale(1.06);
    box-shadow: 2px 2px 5px black;
}

#guideh1{
    display: inline;
}

form{
    display: inline;
}

.startstopbtn{
    position: relative;
    top:18rem;
}

.gamebtn{
    background-color: black;
    color:white;
    border-radius: 2rem;
    width:fit-content;
    height: fit-content;
    font-size: larger;
    font-weight: bolder;
    padding: 0.5rem;
    transition: all 0.3s ease-in-out 0s;
}

.gamebtn:hover{
    transform: scale(1.1);
    box-shadow: 3px 3px 5px black;
}

@media(max-width:1000px){
    body{
        text-align: center;
    }
    .box-container{
    position: fixed;
    left:16%;
    text-align: center;
    }
}